How to Use Calibre to Convert eBooks to KFX Format (for the Enhanced Kindle Typography)

23480216050_e7b75ef161_hWhen Amazon announced the KFX format last year, they teased ebookophiles with features like hyphenation, improved kerning,  and dropcaps, features which one could find in ebooks bought in the Kindle Store but you couldn't make for yourself.

Now you can.

Early last month Amazon released a beta version of the Kindle Previewer tool which lets ebook makers convert and preview their ebooks to see how they will look in the new format, and now there's an even easier at-home option.

A new plugin for Calibre called KFX Output lets you convert ebooks into KFX format to make use of Amazon’s enhanced typesetting. It calls on that beta release of the Kindle Previewer tool to make the ebooks, and then add them to your calibre library.

If you would like to try it yourself, here's what you need to do:

  1. Install Kindle Previewer 3,
  2. Install calibre, and
  3. Install the KFX plugin (from inside calibre).

The plugin will only work with Epub files, so any ebook you want to convert to KFX will first have to be converted to Epub.

Or at least that is the way it is supposed to work; it won't work for me (one of my competitors is having better luck, however). I've tried to convert a dozen ebooks over the weekend, and all attempts threw errors. (The plugin was just released, and it calls on a beta app, so this is not unexpected.)

Edit: It's working for me now.

If you would like to try it yourself, I'd love to hear about your success and failures. And if you have trouble with the plugin, or want to offer feedback and contribute to its development, please join the ongoing discussion over at MobileRead Forums.

I'm especially looking forward to Kindle screenshots showing your converted ebook; it is going to be nifty to see that readers finally have access to the proprietary features Amazon launched last year.

image by M. Martin Vicente

About Nate Hoffelder (11221 Articles)
Nate Hoffelder is the founder and editor of The Digital Reader:"I've been into reading ebooks since forever, but I only got my first ereader in July 2007. Everything quickly spiraled out of control from there. Before I started this blog in January 2010 I covered ebooks, ebook readers, and digital publishing for about 2 years as a part of MobileRead Forums. It's a great community, and being a member is a joy. But I thought I could make something out of how I covered the news for MobileRead, so I started this blog."

9 Comments on How to Use Calibre to Convert eBooks to KFX Format (for the Enhanced Kindle Typography)

  1. “controverted” ebook? 😉

  2. Technically you could do dropcaps just fine via EPUB>KindleGen prior to this. I’m very curious about this though as I was having an iPad for Kindle “Enhanced Typesetting” issue related to losing indents. Time to do some tests…

  3. “3. Install the KFX plugin (from inside calibre)”. Can you give explicit instructions on how to do this? I’ve installed the viewer and have downloaded calibre-2.63.0-x86_64.txz. The reader has six folders: FONTS; IMAGEFORMATS; LIB; LOCALE; MEDIASERVICE; PLATFORMS. They do not accept txz format. Thanks in advance.

    • Sure!

      You can install plugins by first selecting the “get plugins” option under the preferences menu (see the screenshot). Search for the text “kfx output”, and then select the plugin from the list.

      But TBH I’m not sure you have all of calibre installed.

  4. Thanks much. I’ll get on it when I recharge my batteries. It’s an energy-depleting process for an old guy.

  5. Tried it today. It was able to convert some small sized epub but failed to convert even 2mb sized epub file. Some file named imageviewer crashed several times. May be it’ll take some more time to be mature.

2 Trackbacks & Pingbacks

  1. Calibre breakthrough: Convert e-books to the new Kindle KFX format with enhanced Typesetting - TeleRead News: E-books, publishing, tech and beyond
  2. Calibre breakthrough: Convert e-books to the new Kindle KFX format with enhanced Typesetting – Teknoids News

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